Interface enhancement of spin-polar phonon coupling in perovskite multiferroic superlattices

First-principles calculations are carried out for CaMnO3/BaTiO3 short-period superlattices with epitaxial strain corresponding to growth on a NdGaO3 substrate. The ferroelectricity and antiferrodistortion are analyzed under different magnetic orderings. It reveals that MnO6 octohedral rotation is greatly suppressed at the interfaces, which effectively increases the spin-polar phonon coupling in CaMnO3. Besides the conventional epitaxial-strain method, this mechanism provides an alternative way in engineering the spin-lattice coupling materials for an enhanced functionality. Copyright (C) EPLA, 2012